t=tata
m=mama
c=copil
t+m+c=68 (in prezent)
t-7+m-7+c-7=47 (acum 7 ani)
a) t+8+m+8+c+8=
t+m+c+24=
68+24=92 (peste 8 ani)
t=24+c ==>c=t-24
m=t-1
t-1+t+t-24=68
3t-25=68
3t=93
t=31
m=30
c=31-24=7
